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Wolf M, Heni M, Hennige AM, Sippel K, Cegan A, Higuita LMS, Martus P, Häring HU, Fritsche A, Peter A. Acylated- and unacylated ghrelin during an oral glucose tolerance test in humans at risk for type 2 diabetes mellitus. Int J Obes (Lond) 2023; 47:825-832. [PMID: 37420007 PMCID: PMC10439001 DOI: 10.1038/s41366-023-01327-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 11/24/2022] [Accepted: 06/01/2023] [Indexed: 07/09/2023]
Abstract
BACKGROUND/OBJECTIVES The orexigenic peptide hormone ghrelin has been implicated in the pathophysiology of obesity and type 2 diabetes mellitus through its effects on nutrient homeostasis. Ghrelin is subject to a unique post-translational acyl modification regulating its biochemical activity. SUBJECTS/METHODS In this study we aimed to investigate the relation of acylated (AcG) as well as unacylated ghrelin (UnG) with body weight and insulin resistance in the fasting (n = 545) and post-oral glucose tolerance test (oGTT) state (n = 245) in a metabolically well characterized cohort covering a broad range of BMI (17.95 kg/m²-76.25 kg/m²). RESULTS Fasting AcG (median 94.2 pg/ml) and UnG (median 175.3 pg/ml) were negatively and the AcG/UnG ratio was positively correlated with BMI (all p < 0.0001). Insulin sensitivity (ISI) correlated positively with AcG (p = 0.0014) and UnG (p = 0.0004) but not with the AcG/UnG ratio. In a multivariate analysis, including ISI and BMI, only BMI, but not ISI was independently associated with AcG and UnG concentrations. Significant changes of AcG and UnG concentrations were detectable after oGTT stimulation, with slight decreases after 30 min and increases after 90-120 min. Subject stratification into BMI-divergent groups revealed more pronounced AcG increases in the two groups with BMI < 40 kg/m². CONCLUSION Our data demonstrate lower concentrations for both AcG and UnG with increasing BMI as well as an increased proportion of the biologically active, acylated form of ghrelin giving point to pharmacologic intervention in ghrelin acylation and/or increase in UnG for treatment of obesity despite decreased absolute AcG levels.
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Affiliation(s)
- Magnus Wolf
- Department for Diagnostic Laboratory Medicine, Institute for Clinical Chemistry and Pathobiochemistry, University Hospital of Tübingen, Tübingen, Germany
- Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
- Department for Diagnostic Laboratory Medicine, Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital of Tübingen, Tübingen, Germany
| | - Martin Heni
- Department for Diagnostic Laboratory Medicine, Institute for Clinical Chemistry and Pathobiochemistry, University Hospital of Tübingen, Tübingen, Germany
- Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
- Department for Internal Medicine IV, Division for Diabetology, Endocrinology and Nephrology, University Hospital of Tübingen, Tübingen, Germany
- Division of Endocrinology and Diabetology, Department of Internal Medicine 1, University Hospital Ulm, Ulm, Germany
| | | | - Katrin Sippel
- Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - Alexander Cegan
- Department of Biological and Biochemical Sciences, Faculty of Chemical Technology, University of Pardubice, Pardubice, Czech Republic
| | - Lina María Serna Higuita
- Institute for Clinical Epidemiology and applied Biostatistics, University of Tübingen, Tübingen, Germany
| | - Peter Martus
- Institute for Clinical Epidemiology and applied Biostatistics, University of Tübingen, Tübingen, Germany
| | - Hans-Ulrich Häring
- Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
- Department for Internal Medicine IV, Division for Diabetology, Endocrinology and Nephrology, University Hospital of Tübingen, Tübingen, Germany
| | - Andreas Fritsche
- Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
- Department for Internal Medicine IV, Division for Diabetology, Endocrinology and Nephrology, University Hospital of Tübingen, Tübingen, Germany
| | - Andreas Peter
- Department for Diagnostic Laboratory Medicine, Institute for Clinical Chemistry and Pathobiochemistry, University Hospital of Tübingen, Tübingen, Germany.
- Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany.
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Caputo M, Pigni S, Agosti E, Daffara T, Ferrero A, Filigheddu N, Prodam F. Regulation of GH and GH Signaling by Nutrients. Cells 2021; 10:1376. [PMID: 34199514 PMCID: PMC8227158 DOI: 10.3390/cells10061376] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/27/2021] [Accepted: 05/28/2021] [Indexed: 02/06/2023] Open
Abstract
Growth hormone (GH) and insulin-like growth factor-1 (IGF-I) are pleiotropic hormones with important roles in lifespan. They promote growth, anabolic actions, and body maintenance, and in conditions of energy deprivation, favor catabolic feedback mechanisms switching from carbohydrate oxidation to lipolysis, with the aim to preserve protein storages and survival. IGF-I/insulin signaling was also the first one identified in the regulation of lifespan in relation to the nutrient-sensing. Indeed, nutrients are crucial modifiers of the GH/IGF-I axis, and these hormones also regulate the complex orchestration of utilization of nutrients in cell and tissues. The aim of this review is to summarize current knowledge on the reciprocal feedback among the GH/IGF-I axis, macro and micronutrients, and dietary regimens, including caloric restriction. Expanding the depth of information on this topic could open perspectives in nutrition management, prevention, and treatment of GH/IGF-I deficiency or excess during life.
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Affiliation(s)
- Marina Caputo
- SCDU of Endocrinology, University Hospital Maggiore della Carità, 28100 Novara, Italy; (M.C.); (S.P.); (T.D.); (A.F.)
- Department of Health Sciences, Università del Piemonte Orientale, 28100 Novara, Italy;
| | - Stella Pigni
- SCDU of Endocrinology, University Hospital Maggiore della Carità, 28100 Novara, Italy; (M.C.); (S.P.); (T.D.); (A.F.)
| | - Emanuela Agosti
- Department of Health Sciences, Università del Piemonte Orientale, 28100 Novara, Italy;
| | - Tommaso Daffara
- SCDU of Endocrinology, University Hospital Maggiore della Carità, 28100 Novara, Italy; (M.C.); (S.P.); (T.D.); (A.F.)
| | - Alice Ferrero
- SCDU of Endocrinology, University Hospital Maggiore della Carità, 28100 Novara, Italy; (M.C.); (S.P.); (T.D.); (A.F.)
| | - Nicoletta Filigheddu
- Department of Translational Medicine, Università del Piemonte Orientale, 28100 Novara, Italy;
| | - Flavia Prodam
- SCDU of Endocrinology, University Hospital Maggiore della Carità, 28100 Novara, Italy; (M.C.); (S.P.); (T.D.); (A.F.)
- Department of Health Sciences, Università del Piemonte Orientale, 28100 Novara, Italy;
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Gwin JA, Leidy HJ. A Review of the Evidence Surrounding the Effects of Breakfast Consumption on Mechanisms of Weight Management. Adv Nutr 2018; 9:717-725. [PMID: 30204837 PMCID: PMC6247188 DOI: 10.1093/advances/nmy047] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The recommendation to eat breakfast has received scrutiny due to insufficient causal evidence for improvements in weight management. Despite the limited number of randomized controlled trials examining the effects of breakfast consumption compared with skipping breakfast on weight loss, an increasing number of studies target the hormonal and behavioral mechanisms underlying weight management. This review provides a comprehensive examination of the intervention-based clinical trials that test whether breakfast consumption improves appetite control and satiety as well as energy expenditure compared with skipping breakfast. Several factors were considered when interpreting the body of evidence. These include, but were not limited to, the following: the composition of breakfast, with a specific focus on dietary protein; meal size and form; and habitual breakfast behaviors. The evidence within this review shows positive to neutral support for the inclusion of breakfast for improvements in appetite control, satiety, and postprandial energy expenditure. The protein content, energy content, and form of the meal (i.e., beverages compared with foods) are key modulating factors for ingestive behavior and energy expenditure mechanisms. Specifically, breakfast meals containing a larger amount of protein (≥30 g protein/meal) and energy (≥350 kcal/meal) and provided as solid foods increased the magnitude of the appetite and satiety response compared with breakfast skipping. Longer-term randomized controlled trials including the measurement of ingestive behavior and weight management are needed to identify the role of breakfast for health promotion.
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Affiliation(s)
- Jess A Gwin
- Department of Nutrition Science, Purdue University, West Lafayette, IN
| | - Heather J Leidy
- Department of Nutrition Science, Purdue University, West Lafayette, IN
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4
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Kuppens RJ, Delhanty PJD, Huisman TM, van der Lely AJ, Hokken-Koelega ACS. Acylated and unacylated ghrelin during OGTT in Prader-Willi syndrome: support for normal response to food intake. Clin Endocrinol (Oxf) 2016; 85:488-94. [PMID: 26850227 DOI: 10.1111/cen.13036] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 12/20/2015] [Accepted: 02/02/2016] [Indexed: 01/13/2023]
Abstract
BACKGROUND Prader-Willi syndrome (PWS) is characterized by hyperphagia with impaired satiety. PWS patients have very high acylated ghrelin (AG) with normal unacylated ghrelin (UAG) levels, resulting in an elevated AG/UAG ratio, suggesting an intrinsic defect in the ghrelin regulation. Normally, food intake induces satiety and a drop in AG and UAG levels, but it is unknown if these levels also decline in PWS. OBJECTIVE To evaluate whether the high AG levels in PWS decline in response to glucose intake during an oral glucose tolerance test (OGTT), and to investigate the effects of growth hormone (GH) treatment on this response. METHOD Serum levels of AG, UAG and AG/UAG ratio during an OGTT were determined in 24 GH-treated patients with PWS (median age 19·0, range 14·2-25·9 years) and in 10 GH-stop patients (of whom five were in GH-treated group; 18·5, 14·5-20·3 years). RESULTS In GH-treated and GH-stop young adults with PWS, there was a sharp decline of AG levels and a decrease of UAG levels in the first 30 min after the glucose load, which resulted in a lower AG/UAG ratio. GH-treated patients had significantly lower AG levels than GH-stop patients at baseline and during the OGTT. All UAG levels and AG/UAG ratios were lower in the GH-treated patients, although not significantly. CONCLUSIONS In young adults with PWS, an oral glucose load significantly reduces AG and UAG levels, suggesting normal regulation of the ghrelin axis by food intake. GH treatment results in lower AG levels at baseline and during OGTT, suggesting a more favourable metabolic profile. Our findings might suggest that the impaired satiety is not the result of an abnormal response of the orexigenic ghrelin to food intake.
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Affiliation(s)
- R J Kuppens
- Dutch Growth Research Foundation, Rotterdam, The Netherlands
- Subdivision of Endocrinology, Department of Pediatrics, Erasmus University Medical Center-Sophia Children's Hospital, Rotterdam, The Netherlands
| | - P J D Delhanty
- Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - T M Huisman
- Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - A J van der Lely
- Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - A C S Hokken-Koelega
- Dutch Growth Research Foundation, Rotterdam, The Netherlands
- Subdivision of Endocrinology, Department of Pediatrics, Erasmus University Medical Center-Sophia Children's Hospital, Rotterdam, The Netherlands
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Nakato J, Aoki H, Iwakura H, Suzuki H, Kanamoto R, Ohinata K. Soy-ghretropin, a novel ghrelin-releasing peptide derived from soy protein. FEBS Lett 2016; 590:2681-9. [DOI: 10.1002/1873-3468.12306] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 06/22/2016] [Accepted: 06/23/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Junya Nakato
- Division of Food Science and Biotechnology; Graduate School of Agriculture; Kyoto University; Uji Japan
| | - Hayato Aoki
- Division of Food Science and Biotechnology; Graduate School of Agriculture; Kyoto University; Uji Japan
| | - Hiroshi Iwakura
- Medical Innovation Center; Kyoto University Graduate School of Medicine; Japan
| | | | - Ryuhei Kanamoto
- Division of Food Science and Biotechnology; Graduate School of Agriculture; Kyoto University; Uji Japan
| | - Kousaku Ohinata
- Division of Food Science and Biotechnology; Graduate School of Agriculture; Kyoto University; Uji Japan
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Iwakura H, Kangawa K, Nakao K. The regulation of circulating ghrelin - with recent updates from cell-based assays. Endocr J 2015; 62:107-22. [PMID: 25273611 DOI: 10.1507/endocrj.ej14-0419] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Ghrelin is a stomach-derived orexigenic hormone with a wide range of physiological functions. Elucidation of the regulation of the circulating ghrelin level would lead to a better understanding of appetite control in body energy homeostasis. Earlier studies revealed that circulating ghrelin levels are under the control of both acute and chronic energy status: at the acute scale, ghrelin levels are increased by fasting and decreased by feeding, whereas at the chronic scale, they are high in obese subjects and low in lean subjects. Subsequent studies revealed that nutrients, hormones, or neural activities can influence circulating ghrelin levels in vivo. Recently developed in vitro assay systems for ghrelin secretion can assess whether and how individual factors affect ghrelin secretion from cells. In this review, on the basis of numerous human, animal, and cell-based studies, we summarize current knowledge on the regulation of circulating ghrelin levels and enumerate the factors that influence ghrelin levels.
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Affiliation(s)
- Hiroshi Iwakura
- Medical Innovation Center, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
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Ballard TP, Melby CL, Camus H, Cianciulli M, Pitts J, Schmidt S, Hickey MS. Effect of resistance exercise, with or without carbohydrate supplementation, on plasma ghrelin concentrations and postexercise hunger and food intake. Metabolism 2009; 58:1191-9. [PMID: 19497597 DOI: 10.1016/j.metabol.2009.03.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Accepted: 03/23/2009] [Indexed: 02/01/2023]
Abstract
The effects of resistance exercise with and without carbohydrate (CHO) supplementation on hunger, postexercise food intake, and plasma ghrelin, an orexigenic gastric peptide, are poorly characterized. We examined the individual and combined effects of a resistance exercise bout and CHO consumption on plasma ghrelin and postexercise food intake. Twenty-one apparently healthy young male participants ([mean +/- SD] age = 20 +/- 1.8 years, body mass index = 24.8 +/- 3.3 kg/m(2)) completed in random order 3 treatment conditions: (1) ExCHO-80-minute resistance exercise bout while consuming CHO ( approximately 77 g CHO, 306 kcal); (2) ExPLA-identical exercise with a non=caloric placebo; and (3) NoExCHO-no-exercise trial of quiet sitting and CHO consumption. Blood samples were obtained before, during, and immediately postexercise, and 110 minutes after exercise. At 2 hours postexercise, they were provided a buffet of food from which they ate ad libitum. There was a significant time x treatment interaction for plasma ghrelin caused by a decline from pre- to postexercise in the 2 exercise conditions compared with an increase over time in the NoExCHO condition. At 110 minutes postexercise, ghrelin was 21% and 13% lower in ExCHO and ExPLA compared with NoExCHO (both Ps < .05). However, despite the lower ghrelin concentrations for the 2 exercise conditions, the subjective ratings of hunger were not lower for these conditions compared with the NoExCHO. There were no differences in absolute ad libitum energy intake from the buffet among the 3 conditions, but relative energy intake from the buffet accounting for the estimated cost of exercise was lowest among the 2 exercise conditions. We conclude that (1) weight lifting lowers plasma ghrelin concentrations during exercise and attenuates its rise during the postexercise period in young men and (2) the lower plasma ghrelin concentration is not associated with lower subjective feelings of hunger measured 100 minutes postexercise, but is associated with a lower relative food intake.
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Affiliation(s)
- Tasha P Ballard
- Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO 80523, USA
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Prodam F, Bellone S, Grugni G, Crinò A, Ragusa L, Franzese A, Di Battista E, Corrias A, Walker G, Rapa A, Aimaretti G, Bona G. Influence of age, gender, and glucose tolerance on fasting and fed acylated ghrelin in Prader Willi syndrome. Clin Nutr 2009; 28:94-9. [PMID: 19150743 DOI: 10.1016/j.clnu.2008.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 11/14/2008] [Accepted: 12/07/2008] [Indexed: 01/12/2023]
Abstract
BACKGROUND & AIMS Prader Willi syndrome (PWS) is a genetic syndrome characterized by hyperphagia, morbid obesity, relative hypoinsulinemia and normal insulin sensitivity. PWS presents higher total (TG) and acylated ghrelin (AG) levels. The cause of this increase as well as the modulation of ghrelin secretion in fasting and feeding in relation to other metabolic parameters and glucose tolerance in PWS is largely unknown. METHODS We studied TG and AG at fasting in PWS children (14) and adults (18). We also studied TG and AG response to a mixed standardized light breakfast (SLB) in PWS adults without (AD-GT) and with glucose intolerance (AD-GI) at OGTT. RESULTS TG and AG were higher in children than in adults (p<0.05). AG was higher in adult males (p<0.001). Fasting AG and AG/TG ratio were lower in AD-GI than in AD-GT (p<0.05). TG, but not AG, decreased in AD-GT (p<0.006), whereas AG, but not TG, increased in AD-GI (p<0.03) post-SLB. Fasting TG and AG were negatively predicted by fasting insulin (p<0.05). Post-SLB AG was positively predicted by glucose during OGTT (p<0.04). CONCLUSIONS Fasting and post-meal AG levels are influenced by glucose tolerance in PWS, suggesting that AG derangement might have a role in the development of glucose intolerance.
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Affiliation(s)
- Flavia Prodam
- Division of Paediatrics, Department of Medical Science, University of Piemonte Orientale, Novara, Italy.
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Abstract
We investigated ghrelin, leptin, glucose, and insulin response to an oral glucose tolerance test among children receiving antipsychotics. Hormone concentrations were assayed at fasting, 30, 60, and 120 minutes. The sample was composed of 9 obese (defined as at or above the 95th percentile for age) and 10 overweight/normal children (defined as less than the 95th percentile in weight) based on National Institutes of Health criteria. Ages of the obese (10.7 +/- 3.4 years) and the overweight/normal (13.1 +/- 1.6 years) did not differ. Leptin was significantly higher among the obese group and did not change consequent to glucose. Ghrelin did not differ between the groups, and when the values were combined, ghrelin decreased at 30 minutes and approached fasting concentrations at 120 minutes. To further explore our data, we constituted separate groups based upon z score changes. When weight gain defined as an increase in z score (X = 0.4), the nongainers showed leptin concentrations to decrease over time. Findings encourage further oral glucose tolerance test studies to explain the leptin response to weight gain seen among children receiving antipsychotic medication.
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Giménez-Palop O, Giménez-Pérez G, Mauricio D, González-Clemente JM, Potau N, Berlanga E, Trallero R, Laferrère B, Caixàs A. A lesser postprandial suppression of plasma ghrelin in Prader-Willi syndrome is associated with low fasting and a blunted postprandial PYY response. Clin Endocrinol (Oxf) 2007; 66:198-204. [PMID: 17223988 DOI: 10.1111/j.1365-2265.2006.02707.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVE Ghrelin and polipeptide YY (PYY) are involved in the regulation of food intake. We evaluated these two peptides and their possible relationship in adult patients with Prader-Willi syndrome (PWS). PATIENTS Seven patients with PWS, 16 age-sex-BMI matched obese and 42 age-sex matched lean subjects. DESIGN AND MEASUREMENTS Fasting plasma PYY and ghrelin levels were measured in all subjects and, postprandially until 6 h, in seven matched subjects of each group. RESULTS Fasting ghrelin levels were higher in PWS than in the other two groups. Fasting PYY levels were lower in patients with PWS than in lean subjects but similar to those in obese subjects. The postprandial decrease in ghrelin concentrations was lower in PWS as compared to the other two groups and therefore the 6-h-postprandial area under the curve (AUC) for ghrelin was higher in PWS than in obese subjects. PYY response after the meal was blunted in patients with PWS, but not in the other two groups that showed a peak at 60 min The AUC for PYY was lower in PWS as compared to the other two groups. Fasting PYY levels correlated negatively with fasting ghrelin levels and with ghrelin AUC and they were the only predictor for ghrelin AUC (beta = -0.464, P = 0.034). The increase in PYY correlated negatively with the decrease in ghrelin at times 60 min and 120 min in PWS. CONCLUSIONS In PWS, the low decrease in postprandial ghrelin levels could be related to the low fasting PYY concentrations and their blunted postprandial response.
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Affiliation(s)
- Olga Giménez-Palop
- Unit of Diabetes Endocrinology and Nutrition, Hospital de Sabadell, Sabadell, Spain
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Dimaraki EV, Jaffe CA. Role of endogenous ghrelin in growth hormone secretion, appetite regulation and metabolism. Rev Endocr Metab Disord 2006; 7:237-49. [PMID: 17195943 DOI: 10.1007/s11154-006-9022-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Ghrelin, a 28-amino acid hormone that is acylated post-translation, is the endogenous ligand for the growth hormone (GH) secretagogue (GHS) receptor (GHS-R). The highest concentrations of ghrelin are found in the stomach; however ghrelin peptide is also present in hypothalamic nuclei known to be important in the control of GH and feeding behavior. Exogenous ghrelin potently stimulates pituitary GH release through a mechanism that is dependent, in part, on endogenous GH-releasing hormone. Whether endogenous ghrelin plays a role in the control of GH secretion and growth is not clear and ghrelin deficient animals appear to grow normally. In contrast, experimental animal and clinical data suggest that abnormalities in GHS-R signaling could impact growth. Ghrelin or other GHS are clinically useful for GH-testing and limited data suggest that they might be useful in the treatment of some patients with GH deficiency. Substantial data have implicated ghrelin as an important regulator of feeding behavior and energy equilibrium. Ghrelin has a potent orexigenic effect in both animals and humans and this effect is mediated through hypothalamic neuropeptide Y (NPY) and Agouti-related peptide (AgRP). Appetite simulation coupled with other metabolic effects promotes weight gain during chronic treatment with ghrelin. These metabolic effects are in part mediated through an increase in respiratory quotient (VQ). Presence of ghrelin appears to be necessary for the development of obesity in some animal models. Whether abnormalities in ghrelin signaling are involved in human obesity is not yet known.
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Affiliation(s)
- Eleni V Dimaraki
- Department of Medicine, Division of Endocrinology and Metabolic Diseases, Evanston Northwestern Healthcare and Northwestern University Feinberg School of Medicine, Evanston, IL 60201, USA
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Prodam F, Me E, Riganti F, Gramaglia E, Bellone S, Baldelli R, Rapa A, van der Lely AJ, Bona G, Ghigo E, Broglio F. The nutritional control of ghrelin secretion in humans: the effects of enteral vs. parenteral nutrition. Eur J Nutr 2006; 45:399-405. [PMID: 17061019 DOI: 10.1007/s00394-006-0613-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2006] [Accepted: 08/02/2006] [Indexed: 11/27/2022]
Abstract
BACKGROUND The nutritional control of ghrelin has not been fully clarified yet. Particularly, the influence of aminoacids and lipids is controversial and, moreover, whether the intraluminal gastric contact with nutrients is required or if the modulatory action of nutrients on ghrelin secretion is mediated by insulin is still matter of debate. AIM OF THE STUDY To clarify the role of nutrients in the control of ghrelin secretion evaluating the effects of intravenous and oral lipids and aminoacids compared with glucose and fructose load in healthy subjects. METHODS A total of 6 healthy overnight-fasted volunteers underwent the following testing sessions: (a) iv arginine (ARG, 0.5 g/kg); (b) oral protein load (PRO, 50 g); (c) iv lipid-heparin infusion (Li He, Intralipid 10% 250 ml); (d) oral fat load (OIL, soy oil 40 g); (e) oral glucose load (OGL, 100 g); (f) oral fructose load (OFL, 100 g); (g) iv saline (SAL, 3 ml); (h) oral water load (WL, 200 ml). Total ghrelin, insulin, and glucose were assayed every 15 min from 0 up to +180 min. RESULTS WL and SAL did not modify insulin, glucose and ghrelin. ARG induced a prompt but transient increase (P < 0.05) of insulin and glucose (P < 0.01), without modifying ghrelin secretion. PRO induced a mild but sustained increase of insulin secretion (P < 0.05) without affecting glucose and ghrelin. Li-He progressively increased circulating glucose (P < 0.01) without modifying insulin and ghrelin secretion. No significant variations in circulating glucose, insulin, and ghrelin occurred after OIL. OGL significantly (P < 0.01) increased insulin and glucose levels and progressively decreased (P < 0.05) ghrelin levels. OFL induced a mild (P < 0.05) increase of insulin without modifying glucose levels. Similarly, OFL was followed by a milder decrease (P < 0.05) of ghrelin levels. CONCLUSIONS Differently from carbohydrates and independently from their modulatory effect on insulin secretion and glucose levels, both lipids and aminoacids play a negligible role in the acute control of ghrelin secretion either after acute enteral and parenteral administration.
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Affiliation(s)
- Flavia Prodam
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Turin, c.so Dogliotti, 14 Turin, Italy
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Gordon ME, McKeever KH. Oral and intravenous carbohydrate challenges decrease active ghrelin concentrations and alter hormones related to control of energy metabolism in horses1. J Anim Sci 2006; 84:1682-90. [PMID: 16775051 DOI: 10.2527/jas.2005-484] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
This study tested the hypothesis that grain and intravenous dextrose challenges would alter plasma concentrations of active ghrelin, adiponectin, leptin, glucose, insulin, and cortisol in Standardbred mares. To deliver 0.5 g of glucose (dextrose solution for the intravenous test)/kg of BW, mares received intravenous dextrose (50% solution) or oral grain administration in 2 trials. In response to the oral grain challenge, plasma glucose and insulin concentrations increased (P < 0.001) by 56 and 802%, respectively. Plasma ghrelin concentration initially decreased (P < 0.001) by 40%, then subsequently increased (P < 0.05) from its nadir by 259%. Plasma leptin concentration decreased (P = 0.002) 17% compared with baseline. There was no change (P = 0.34) in plasma adiponectin concentration in response to oral grain challenge; however, plasma cortisol concentrations decreased (P < 0.001) by 24%. In response to the intravenous dextrose challenge, plasma glucose and insulin concentrations increased (P < 0.001) by 432 and 395%, respectively. Plasma active ghrelin concentration initially decreased (P < 0.001) by 56%, then subsequently increased (P < 0.001) from its nadir by 314%. Plasma leptin concentration also increased (P < 0.001) by 33% compared with baseline. There was no change (P = 0.18) in plasma adiponectin concentration throughout the dextrose challenge. Plasma cortisol concentration increased (P = 0.027) by 20%. Hence, oral grain and intravenous nutrient challenges have the ability to alter variables potentially related to energy metabolism in mares, with acute changes in glucose and insulin possibly modulating changes in ghrelin and leptin.
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Affiliation(s)
- M E Gordon
- Equine Science Center, Department of Animal Sciences, Rutgers, the State University of New Jersey, 84 Lipman Drive, New Brunswick 08901, USA
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Baldelli R, Bellone S, Castellino N, Petri A, Rapa A, Vivenza D, Bellone J, Broglio F, Ghigo E, Bona G. Oral glucose load inhibits circulating ghrelin levels to the same extent in normal and obese children. Clin Endocrinol (Oxf) 2006; 64:255-9. [PMID: 16487433 DOI: 10.1111/j.1365-2265.2006.02441.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE The presence of both the GH secretagogue (GHS) receptor and ghrelin in the pancreas indicates an involvement of this hormone in glucose metabolism. Ghrelin secretion is increased by fasting and energy restriction, decreased by food intake, glucose load, insulin and somatostatin in normal adults; however, food intake is not able to inhibit circulating ghrelin levels in children, suggesting that the profile of ghrelin secretion in children is different from that in adults. Moreover, how ghrelin secretion is regulated in childhood as a function of fat mass is still unclear. DESIGN AND SUBJECTS We studied the effect of oral glucose load (75 g solution orally) on circulating total ghrelin levels in 14 obese children (group A, four boys and 10 girls, aged 9.3 +/- 2.3 years) and 10 lean children (group B, five boys and five girls, aged 9.7 +/- 3.8 years). MEASUREMENTS In all the sessions, blood samples were collected every 30 min from 0 up to +120 min. GH, insulin and glucose levels were assayed at each time point. RESULTS Glucose peaks following an oral glucose tolerance test (OGTT) in groups A and B were similar; however, both basal and OGTT-stimulated insulin levels in group A were higher than in group B (P < 0.05). Basal total ghrelin levels in group A (281.3 +/- 29.5 pg/ml) were lower (P < 0.0005) than in group B (563.4 +/- 81.5 pg/ml). In both groups A and B, the OGTT inhibited total ghrelin levels (P < 0.005). In terms of absolute values, total ghrelin levels in group A were lower (P < 0.0005) than those in group B at each time point after glucose load. The percentage nadir in total ghrelin levels recorded in group A (-25% at 90 min) was similar to that recorded in group B (-31% at 120 min). Total ghrelin levels were negatively associated with BMI (r = 0.5, P < 0.005) but not with glucose or insulin levels. CONCLUSION Ghrelin secretion is reduced in obese children. It is, however, equally sensitive in both obese and lean children to the inhibitory effect of oral glucose load.
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Affiliation(s)
- R Baldelli
- Unit of Paediatrics, Department of Medical Sciences, University of Piemonte Orientale A. Avogadro, Novara, Italy
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Jaakkola U, Kuusela T, Jartti T, Pesonen U, Koulu M, Vahlberg T, Kallio J. The Leu7Pro polymorphism of preproNPY is associated with decreased insulin secretion, delayed ghrelin suppression, and increased cardiovascular responsiveness to norepinephrine during oral glucose tolerance test. J Clin Endocrinol Metab 2005; 90:3646-52. [PMID: 15797951 DOI: 10.1210/jc.2005-0153] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
CONTEXT Neuropeptide Y (NPY) plays a role in angiogenesis, cardiovascular regulation, and hormone secretion. The leucine7 to proline7 (Leu7Pro) polymorphism of preproNPY is associated with vascular diseases and has an impact on hormone levels in healthy subjects. OBJECTIVE The current study investigated the role of the Leu7Pro polymorphism in metabolic and cardiovascular autonomic regulation. DESIGN AND SUBJECTS A 5-h oral glucose tolerance test was performed on 27 healthy volunteers representing two preproNPY genotypes (Leu7/Pro7 and Leu7/Leu7) matched for age, sex, body mass index and physical activity. MAIN OUTCOME MEASURES Simultaneously we performed cardiovascular autonomic function tests and plasma measurements of sympathetic transmitters, glucose, insulin, and ghrelin. RESULTS The subjects with Leu7/Pro7 genotype had decreased plasma NPY, norepinephrine (NE), and insulin concentrations and insulin to glucose ratios. The suppression of ghrelin concentrations after glucose ingestion was delayed in these subjects. They also had increased heart rate variability indices and baroreflex sensitivity. However, they displayed significant negative association of NE concentration with variability of low-frequency R-R-intervals and with baroreflex sensitivity. CONCLUSIONS The Leu7Pro polymorphism of preproNPY is related to decreased level of basal sympathetic activity, decreased insulin secretion, and delayed ghrelin suppression during oral glucose tolerance test. The increased responsiveness of autonomic functions to NE associated with the polymorphism may be connected to increased cardiovascular vulnerability.
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Affiliation(s)
- Ulriikka Jaakkola
- Department of Pharmacology and Clinical Pharmacology, University of Turku, Itäinen Pitkäkatu 4, FI-20520 Turku, Finland.
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Ghigo E, Broglio F, Arvat E, Maccario M, Papotti M, Muccioli G. Ghrelin: more than a natural GH secretagogue and/or an orexigenic factor. Clin Endocrinol (Oxf) 2005; 62:1-17. [PMID: 15638864 DOI: 10.1111/j.1365-2265.2004.02160.x] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Ghrelin, an acylated peptide produced predominantly by the stomach, has been discovered to be a natural ligand of the growth hormone secretagogue receptor type 1a (GHS-R1a). Ghrelin has recently attracted considerable interest as a new orexigenic factor. However, ghrelin exerts several other neuroendocrine, metabolic and also nonendocrine actions that are explained by the widespread distribution of ghrelin and GHS-R expression. The likely existence of GHS-R subtypes and evidence that the neuroendocrine actions, but not all the other actions, of ghrelin depend on its acylation in serine-3 revealed a system whose complexity had not been completely explored by studying synthetic GHS. Ghrelin secretion is mainly regulated by metabolic signals and, in turn, the modulatory action of ghrelin on the control of food intake and energy metabolism seems to be among its most important biological actions. However, according to a recent study, ghrelin-null mice are neither anorectics nor dwarfs and this evidence clearly depicts a remarkable difference from leptin null mice. Nevertheless, the original and fascinating story of ghrelin, as well as its potential pathophysiological implications in endocrinology and internal medicine, is not definitively cancelled by these data as GHS-R1a null aged mice show significant alterations in body composition and growth, in glucose metabolism, cardiac function and contextual memory. Besides potential clinical implications for natural or synthetic ghrelin analogues acting as agonists or antagonists, there are several open questions awaiting an answer. How many ghrelin receptor subtypes exist? Is ghrelin 'the' or just 'a' GHS-R ligand? That is, are there other natural GHS-R ligands? Is there a functional balance between acylated and unacylated ghrelin forms, potentially with different actions? Within the next few years suitable answers to these questions will probably be found, making it possible to gain a better knowledge of ghrelin's potential clinical perspectives.
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Affiliation(s)
- E Ghigo
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Turin, Italy.
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Broglio F, Gottero C, Prodam F, Destefanis S, Gauna C, Me E, Riganti F, Vivenza D, Rapa A, Martina V, Arvat E, Bona G, van der Lely AJ, Ghigo E. Ghrelin secretion is inhibited by glucose load and insulin-induced hypoglycaemia but unaffected by glucagon and arginine in humans. Clin Endocrinol (Oxf) 2004; 61:503-9. [PMID: 15473884 DOI: 10.1111/j.1365-2265.2004.02121.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Circulating ghrelin levels are increased by fasting and decreased by feeding, glucose load, insulin and somatostatin. Whether hyperglycaemia and insulin directly inhibit ghrelin secretion still remains matter of debate. The aim of the present study was therefore to investigate further the regulatory effects of glucose and insulin on ghrelin secretion. DESIGN AND SUBJECTS We studied the effects of glucose [oral glucose tolerance test (OGTT) 100 g orally], insulin-induced hypoglycaemia [ITT, 0.1 IU/kg insulin intravenously (i.v.)], glucagon (1 mg i.v.), arginine (0.5 mg/kg i.v.) and saline on ghrelin, GH, insulin, glucose and glucagon levels in six normal subjects. MEASUREMENTS In all the sessions, blood samples were collected every 15 min from 0 up to + 120 min. Ghrelin, GH, insulin, glucagon and glucose levels were assayed at each time point. RESULTS OGTT increased (P < 0.01) glucose and insulin while decreasing (P < 0.01) GH and ghrelin levels. ITT increased (P < 0.01) GH but decreased (P < 0.01) ghrelin levels. Glucagon increased (P < 0.01) glucose and insulin without modifying GH and ghrelin. Arginine increased (P < 0.01) GH, insulin, glucagon and glucose (P < 0.05) but did not affect ghrelin secretion. CONCLUSIONS Ghrelin secretion in humans is inhibited by OGTT-induced hyperglycaemia and ITT but not by glucagon and arginine, two substances able to increase insulin and glucose levels. These findings question the assumption that glucose and insulin directly regulate ghrelin secretion. On the other hand, ghrelin secretion is not associated with the GH response to ITT or arginine, indicating that the somatotroph response to these stimuli is unlikely to be mediated by ghrelin.
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Affiliation(s)
- Fabio Broglio
- Division of Endocrinology, Department of Internal Medicine, Erasmus University of Rotterdam, the Netherlands
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Bellone S, Castellino N, Broglio F, Rapa A, Vivenza D, Radetti G, Bellone J, Gottero C, Ghigo E, Bona G. Ghrelin secretion in childhood is refractory to the inhibitory effect of feeding. J Clin Endocrinol Metab 2004; 89:1662-5. [PMID: 15070928 DOI: 10.1210/jc.2003-031207] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ghrelin, a natural GH secretagogue, is predominantly produced by the stomach. Ghrelin has other actions including orexant activity, modulation of energy balance, and modulation of endocrine and nonendocrine functions. Ghrelin secretion is increased by fasting and energy restriction but decreased by food intake, glucose, insulin, and somatostatin. Ghrelin secretion does not seem to be a function of age; in fact, morning ghrelin levels after overnight fasting in prepubertal and pubertal children are similar to those in young adults. To clarify whether children and adults have the same sensitivity to the inhibitory effect of food intake, we studied the ghrelin response to a standardized light breakfast (SLB) in 10 prepubertal lean children whose results were compared with those recorded in 19 normal-weight adults. Basal ghrelin levels in children (median, 224.5; 25th to 75th percentile, 122.0-447.7 pg/ml) and adults (338.0; 238.0-512.0 pg/ml) were similar. SLB inhibited ghrelin levels in adults (263.0; 190.0-399.0 pg/ml). However, no change in ghrelin levels after SLB (206.5; 105.0-274.0 pg/ml) was recorded in children. Thus, food intake inhibits ghrelin secretion in adults but not in children. Ghrelin refractoriness to inhibition by food intake in children would reflect a peculiar functional profile of the ghrelin system in childhood.
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Affiliation(s)
- Simonetta Bellone
- Units of Pediatrics, Department of Medical Sciences, University of Piemonte Orientale, 28100 Novara, Italy
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